Teprotumumab effectively reduces proptosis in patients with active thyroid eye disease, according to phase 3 confirmatory trial data presented at the 28th Annual Congress of the American Association of Clinical Endocrinologists (AACE 2019), held April 24 to 28 in Los Angeles, California.
Results from the 24-week OPTIC study (Treatment of Graves’ Orbitopathy to Reduce Proptosis with Teprotumumab Infusions in a Randomized, Placebo-Controlled, Clinical Study; ClinicalTrials.gov identifier: NCT03298867) showed that teprotumumab, an investigational insulin-like growth factor 1 receptor inhibitor, led to a significantly higher percentage of patients achieving the primary end point compared with placebo (82.9% vs 9.5%; P <.001). The primary end point was defined as a ≥2-mm reduction of proptosis from baseline without deterioration of proptosis in the eye not being observed in the study.
The investigators also explored several secondary end points, all of which reached statistical significance. In new findings presented at AACE 2019, researchers reported that patients with active thyroid eye disease receiving teprotumumab had an average reduction of proptosis of 2.82 mm compared with a reduction of 0.54 mm in patients receiving placebo (P <.001). Compared with the placebo group, patients receiving teprotumumab had significantly greater reductions in proptosis at weeks 6, 12, and 18 of the 24-week study period.
In addition, the researchers measured responder rate for treatment with teprotumumab and placebo, defined as a proptosis reduction of ≥2 mm and a Clinical Activity Score improvement of ≥2 points. Clinical Activity Score measured degree of inflammation caused by thyroid eye disease, including pain, swelling, and redness.
Patients receiving teprotumumab had a significantly higher responder rate compared with those receiving placebo at the end of the study (78% vs 7.1%; P <.001), as well as at weeks 6, 12, and 18.
Secondary end points measuring diplopia and Graves Opthalmopathy Quality of Life questionnaire scores also showed improvements from baseline with teprotumumab vs placebo.
As previously reported, adverse events associated with teprotumumab were generally mild to moderate in intensity.
These data support the use of teprotumumab as a treatment for active thyroid eye disease, which currently does not have a treatment approved by the United States Food and Drug Administration.
New Data from Phase 3 Teprotumumab Trial (OPTIC) Shows Dramatic Reduction in Proptosis, or Eye Bulging, the Main Cause of Morbidity in Active Thyroid Eye Disease (TED) [news release]. Dublin, Ireland: Horizon Pharma; April 26, 2019. Accessed April 26, 2019.